Patent GB-486747-A (GB)
Title: Manufacture of pyrazolone derivatives
IPC: C07D403/14
Filed: 1936-11-06
Abstract: The invention relates to the manufacture of 5-pyrazolone derivatives substituted in the 1-position by a group -RXR1NHR11, where R and R1 are residues of the benzene series, R11 is hydrogen or an organic acid radicle, and X is a simple linkage, an oxygen atom, one of the groups -CH : CH-, -CH2-, -NH CO-, or -NHCONH-, or an amino-substituted heterocyclic ring containing carbon and nitrogen, e.g. the residue of a 2 : 5-diamino-1 : 3 : 5-triazine ring, which may be substituted in the 4-position, or the residue of a similarly substituted pyrimidine or quinazoline ring.  Such pyrazolones are prepared from amines of the formula NH2RXR1NHR11, where R, R1 and X are as above and R11 is an organic acid radicle, by diazotizing the amines, reducing the diazo compounds to the corresponding hydrazine derivatives, and condensing the latter with esters of b -ketocarboxylic acids.  The acid radicle R11 may be split off before or after the production of the pyrazlone, and may afterwards be replaced by another acid radicle.  Specified amines for use as starting materials are N-monoacyl derivatives of any of the following compounds: benzidine, tolidine, dianisidine, diphenetidine, 4 : 41-di-aminodiphenyl ether, 4 : 41-diaminostilbene, 4 : 41- or 3 : 31 - diaminodiphenylmethane, 4 : 41-, 4 : 31-, 3 : 41- or 3 : 31-diamonobenzoylaniline, 4 : 41-diaminodiphenylurea, the condensation product from 2 or 3 mols. of m- or p-phenylenediamine and 1 mol. of cyanuric chloride, or the product from 1 mol. of cyanuric chloride, 1 mol. of aniline, and 2 mols. of m- or p-phenylenediamine.  Specified esters of b -ketocarboxylic acids are those of formylacetic, acetoacetic, oxalacetic and benzoylacetic acids and aroyldiacetic acids such as terephthaloyldiacetic acid. The products are useful in the manufacture of azo dyes (cf. Specification 486,660). In the examples, (1) monoacetylbenzidine is diazotized, the diazo solution is treated with stannous chloride, and the hydrazine so obtained, or its hydrochloride, is heated with ethyl acetoacetate, ethyl benzoylacetate, or ethyl oxaloacetate; (2) the hydrazine used in example 1 is boiled with aqueous hydrochloric acid, whereby the acetyl group is split off; the product is then condensed with ethyl acetoacetate.  Samples have been furnished, under Sect. 2 (5), of pyrazolones prepared as described above from the following components, the specified amino compounds being in each case diazotized and reduced to yield a hydrazine, which is then condensed with the specified ketocarboxylic ester: (1) acetoacetic ester and monoacetyl-4 : 41-diaminodiphenyl ether, with intermediate elimination of the acetyl group; (2) acetoacetic ester and monoacetyl-4 : 41-diaminodiphenyl ether; (3) sodium oxalacetic ester and monoacetyl-4 : 41-diaminodiphenyl ether, with intermediate elimination of the acetyl group; (4) acetoacetic ester and monoacetyl - 4 : 41 - diaminodiphenylmethane, with intermediate elimination of the acetyl group; (5) sodium oxalacetic ester and monoacetyl - 4 : 41 - diaminodiphenylmethane, with intermediate elimination of the acetyl group; (6) acetoacetic ester and monoacetyl benzidine, with intermediate elimination of the acetyl group and subsequent acylation with benzoyl chloride; (7) as for sample 6, except that p-toluenesulphochloride is used for the final acylation; (8) sodium oxalacetic ester and monoacetylbenzidine, with intermediate elimination of the acetyl group and subsequent acylation with the condensation product of 1 mol. of cyanuric chloride and 1 mol. of aniline; (9) as for sample 6, except that terephthaloyl chloride is used for the final acylation; (10) as for sample 6, except that cinnamoyl chloride is used for the final acylation; (11) benzoylacetic ester and monoacetylbenzidine, with intermediate elimination of the acetyl group; (12) terephthaloyldiacetic ester and monoacetylbenzidine, with intermediate elimination of the acetyl group; (13) acetoacetic ester and monoacetyl-o, o1-dichlorobenzidine, with intermediate elimination of the acetyl group; (14) sodium oxalacetic ester and monoacetyl-o, o1-dichlorobenzidine, with intermediate elimination of the acetyl group; (15) acetoacetic ester and monoacetyl-o-tolidine, with intermediate elimination of the acetyl group; (16) sodium oxalacetic ester and monoacetyl-o-tolidine, with intermediate elimination of the acetyl group; (17) acetoacetic ester and monoacetyl-4 : 41-diamino diphenylurea (prepared by condensing p-aminoacetanilide with p-nitrophenylurea chloride and reducing the nitro group in the product); (18) acetoacetic ester and 4-(41-acetylaminobenzoyl)amino-1-aminobenzene-2-sulphonic acid (prepared by condensing p-nitrobenzoyl chloride with p-phenylenediaminesulphonic acid, reducing the nitro group in the product, and treating the diamine so obtained with 1 mol. of acetic anhydride); (19) acetoacetic ester and a monoacetyldiaminodisulphonic acid prepared by condensing 1 mol. of cyanuric chloride with 1 mol. each of monoacetyl-p-phenylenediaminesulphonic acid, p-phenylenediaminesulphonic acid, and aniline.  The Specification as open to inspection under Sect. 91 includes an example in which the pyrazolone produced as in example 2 above is acylated by reaction with cyanuric acid, phosgene, or 2 : 3-oxynaphthoic acid chloride. The samples schedule includes a description of the preparation of pyrazolones from (1) sodium oxalacetic ester and monoacetylbenzidine, with intermediate elimination of the acetyl group, subsequent acylation with cyanuric chloride, and a final reaction with aniline, whereby a chlorine atom of the cyanuric residue is replaced by a phenylamino group; the product is identical with sample 8 above; (2) monoacetylbenzidine and acetoacetic ester, with intermediate elimination of the acetyl group and subsequent reaction with 2 : 4-dichlor quinazoline.  This subject-matter does not appear in the Specification as accepted.